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Audio signal conversion

dortbinbir

Apr 21, 2023
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Hello,
I'm making a pre-amp that utilizes TDA7318 (yes its old) and an analog VU-meter (with driver board) along with an Arduino Mega as a controller and a Nextion TFT for display and input.

So far so good, however, the TDA7318 audio output is 4.5V whilst my Vu-meter (nakamichi branded) requires a line-level input. Therefore, a conversion is required between them. I'm just ignoring impedance difference (if any) since it's above my poor electronics knowledge.

Appreciate any help.

Thanks
 

Harald Kapp

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Nov 17, 2011
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Use a resistive voltage divider. Depending on the curent the VU meter requires, you may also use a trim potentiometer to fine-adjust the VU's display.
 

crutschow

May 7, 2021
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You could also use just a trimpot with the resistive element connected between the TDA7318 output and ground, and the wiper connected to the VU meter input.
A 5k to 10kΩ trimpot should likely work.
 

danadak

Feb 19, 2021
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Does the VU meter board require an offset range V span to accommodate it ?

If so this will help, attached.


Regards, Dana.
 

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  • Gain and Offset.pdf
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AnalogKid

Jun 10, 2015
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Can you post any information or links to the VU meter and its board?

ak
 

AnalogKid

Jun 10, 2015
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A VU meter

If that was a response to my question, you misunderstood. I have some familiarity with what a VU meter is (and a copy of Howard Chinn's book).

My question was for the TS, to see exactly what he is working with. There are many things out there that are called a VU meter, but do not meet most of the requirements for one. His meter has a "driver board", and that raises a bunch of questions.

Also, the adafruit link is to a different product line.

ak

 
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